Abstract

In this study, cyclic loading is applied to the specimen placed in an autoclave with varied hydrogen gas pressure. The effect of hydrogen pressure and stress fluctuations on the fatigue crack growth rate is analyzed. The results show that the crack growth rate increases with the increase of hydrogen pressure, and under 3 MPa hydrogen pressure, the crack growth rate can be enhanced by one order compared with that in air. With the increase of loading frequency, the crack propagation rate of a single block decreases in hydrogen, while the crack growth rate remains constant in air. As the maximum stress is fixed during cyclic loading, the fatigue crack growth rate increases with the stress range. Based on the experimental results, a predictive model is proposed to quantify the crack growth rate under different hydrogen pressure and loading conditions.